/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License. 
 *
 */
package org.apache.bcel.classfile;

import java.util.Stack;

/**
 * Traverses a JavaClass with another Visitor object 'piggy-backed' that is
 * applied to all components of a JavaClass object. I.e. this class supplies the
 * traversal strategy, other classes can make use of it.
 * 
 * @version $Id: DescendingVisitor.java 1149459 2011-07-22 04:34:27Z dbrosius $
 * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
 */
public class DescendingVisitor implements Visitor
{
	private JavaClass clazz;

	private Visitor visitor;

	private Stack<Object> stack = new Stack<Object>();

	/**
	 * @return container of current entitity, i.e., predecessor during traversal
	 */
	public Object predecessor()
	{
		return predecessor(0);
	}

	/**
	 * @param level
	 *            nesting level, i.e., 0 returns the direct predecessor
	 * @return container of current entitity, i.e., predecessor during traversal
	 */
	public Object predecessor(int level)
	{
		int size = stack.size();
		if ((size < 2) || (level < 0))
		{
			return null;
		}
		else
		{
			return stack.elementAt(size - (level + 2)); // size - 1 == current
		}
	}

	/**
	 * @return current object
	 */
	public Object current()
	{
		return stack.peek();
	}

	/**
	 * @param clazz
	 *            Class to traverse
	 * @param visitor
	 *            visitor object to apply to all components
	 */
	public DescendingVisitor(JavaClass clazz, Visitor visitor)
	{
		this.clazz = clazz;
		this.visitor = visitor;
	}

	/**
	 * Start traversal.
	 */
	public void visit()
	{
		clazz.accept(this);
	}

	public void visitJavaClass(JavaClass _clazz)
	{
		stack.push(_clazz);
		_clazz.accept(visitor);
		Field[] fields = _clazz.getFields();
		for (int i = 0; i < fields.length; i++)
		{
			fields[i].accept(this);
		}
		Method[] methods = _clazz.getMethods();
		for (int i = 0; i < methods.length; i++)
		{
			methods[i].accept(this);
		}
		Attribute[] attributes = _clazz.getAttributes();
		for (int i = 0; i < attributes.length; i++)
		{
			attributes[i].accept(this);
		}
		_clazz.getConstantPool().accept(this);
		stack.pop();
	}

	public void visitAnnotation(Annotations annotation)
	{
		stack.push(annotation);
		annotation.accept(visitor);
		AnnotationEntry[] entries = annotation.getAnnotationEntries();
		for (int i = 0; i < entries.length; i++)
		{
			entries[i].accept(this);
		}
		stack.pop();
	}

	public void visitAnnotationEntry(AnnotationEntry annotationEntry)
	{
		stack.push(annotationEntry);
		annotationEntry.accept(visitor);
		stack.pop();
	}

	public void visitField(Field field)
	{
		stack.push(field);
		field.accept(visitor);
		Attribute[] attributes = field.getAttributes();
		for (int i = 0; i < attributes.length; i++)
		{
			attributes[i].accept(this);
		}
		stack.pop();
	}

	public void visitConstantValue(ConstantValue cv)
	{
		stack.push(cv);
		cv.accept(visitor);
		stack.pop();
	}

	public void visitMethod(Method method)
	{
		stack.push(method);
		method.accept(visitor);
		Attribute[] attributes = method.getAttributes();
		for (int i = 0; i < attributes.length; i++)
		{
			attributes[i].accept(this);
		}
		stack.pop();
	}

	public void visitExceptionTable(ExceptionTable table)
	{
		stack.push(table);
		table.accept(visitor);
		stack.pop();
	}

	public void visitCode(Code code)
	{
		stack.push(code);
		code.accept(visitor);
		CodeException[] table = code.getExceptionTable();
		for (int i = 0; i < table.length; i++)
		{
			table[i].accept(this);
		}
		Attribute[] attributes = code.getAttributes();
		for (int i = 0; i < attributes.length; i++)
		{
			attributes[i].accept(this);
		}
		stack.pop();
	}

	public void visitCodeException(CodeException ce)
	{
		stack.push(ce);
		ce.accept(visitor);
		stack.pop();
	}

	public void visitLineNumberTable(LineNumberTable table)
	{
		stack.push(table);
		table.accept(visitor);
		LineNumber[] numbers = table.getLineNumberTable();
		for (int i = 0; i < numbers.length; i++)
		{
			numbers[i].accept(this);
		}
		stack.pop();
	}

	public void visitLineNumber(LineNumber number)
	{
		stack.push(number);
		number.accept(visitor);
		stack.pop();
	}

	public void visitLocalVariableTable(LocalVariableTable table)
	{
		stack.push(table);
		table.accept(visitor);
		LocalVariable[] vars = table.getLocalVariableTable();
		for (int i = 0; i < vars.length; i++)
		{
			vars[i].accept(this);
		}
		stack.pop();
	}

	public void visitStackMap(StackMap table)
	{
		stack.push(table);
		table.accept(visitor);
		StackMapEntry[] vars = table.getStackMap();
		for (int i = 0; i < vars.length; i++)
		{
			vars[i].accept(this);
		}
		stack.pop();
	}

	public void visitStackMapEntry(StackMapEntry var)
	{
		stack.push(var);
		var.accept(visitor);
		stack.pop();
	}

	public void visitStackMapTable(StackMapTable table)
	{
		stack.push(table);
		table.accept(visitor);
		StackMapTableEntry[] vars = table.getStackMapTable();
		for (int i = 0; i < vars.length; i++)
		{
			vars[i].accept(this);
		}
		stack.pop();
	}

	public void visitStackMapTableEntry(StackMapTableEntry var)
	{
		stack.push(var);
		var.accept(visitor);
		stack.pop();
	}

	public void visitLocalVariable(LocalVariable var)
	{
		stack.push(var);
		var.accept(visitor);
		stack.pop();
	}

	public void visitConstantPool(ConstantPool cp)
	{
		stack.push(cp);
		cp.accept(visitor);
		Constant[] constants = cp.getConstantPool();
		for (int i = 1; i < constants.length; i++)
		{
			if (constants[i] != null)
			{
				constants[i].accept(this);
			}
		}
		stack.pop();
	}

	public void visitConstantClass(ConstantClass constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitConstantDouble(ConstantDouble constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitConstantFieldref(ConstantFieldref constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitConstantFloat(ConstantFloat constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitConstantInteger(ConstantInteger constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitConstantInterfaceMethodref(
			ConstantInterfaceMethodref constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitConstantLong(ConstantLong constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitConstantMethodref(ConstantMethodref constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitConstantNameAndType(ConstantNameAndType constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitConstantString(ConstantString constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitConstantUtf8(ConstantUtf8 constant)
	{
		stack.push(constant);
		constant.accept(visitor);
		stack.pop();
	}

	public void visitInnerClasses(InnerClasses ic)
	{
		stack.push(ic);
		ic.accept(visitor);
		InnerClass[] ics = ic.getInnerClasses();
		for (int i = 0; i < ics.length; i++)
		{
			ics[i].accept(this);
		}
		stack.pop();
	}

	public void visitInnerClass(InnerClass inner)
	{
		stack.push(inner);
		inner.accept(visitor);
		stack.pop();
	}

	public void visitDeprecated(Deprecated attribute)
	{
		stack.push(attribute);
		attribute.accept(visitor);
		stack.pop();
	}

	public void visitSignature(Signature attribute)
	{
		stack.push(attribute);
		attribute.accept(visitor);
		stack.pop();
	}

	public void visitSourceFile(SourceFile attribute)
	{
		stack.push(attribute);
		attribute.accept(visitor);
		stack.pop();
	}

	public void visitSynthetic(Synthetic attribute)
	{
		stack.push(attribute);
		attribute.accept(visitor);
		stack.pop();
	}

	public void visitUnknown(Unknown attribute)
	{
		stack.push(attribute);
		attribute.accept(visitor);
		stack.pop();
	}

	public void visitAnnotationDefault(AnnotationDefault obj)
	{
		stack.push(obj);
		obj.accept(visitor);
		stack.pop();
	}

	public void visitEnclosingMethod(EnclosingMethod obj)
	{
		stack.push(obj);
		obj.accept(visitor);
		stack.pop();
	}

	public void visitLocalVariableTypeTable(LocalVariableTypeTable obj)
	{
		stack.push(obj);
		obj.accept(visitor);
		stack.pop();
	}

	public void visitParameterAnnotation(ParameterAnnotations obj)
	{
		stack.push(obj);
		obj.accept(visitor);
		stack.pop();
	}
}
